The present invention relates to a disengageable pedal support, in particular for the clutch-actuation pedal in a foot-control unit comprising at least two suspended pedals, in the case of which a brake pedal and a clutch pedal are suspended one beside the other in a common bearing bracket such that they can be pivoted about concentric axes.
In the case of known pedal supports of this type, in each case one pedal is mounted on the bearing shaft of the other pedal, as a result of which, when straightforward plain bearings are used for the support of the pedal shafts both on one another and in the bearing arms of the bearing bracket, this may result in the situation, in particular after a period of operation and increasing contamination or the like of the bearing surfaces, where the pedals influence one another to the effect that the actuation of one pedal has the effect of carrying along the other pedal and thus, for example, actuation of the clutch pedal, which is mounted on the bearing shaft of the brake pedal, causes the brake pedal to be adjusted, albeit to a slight extent. Since such carry-along effects obviously have to be ruled out in the interests of it being possible for the control elements of the vehicle to be operated consistently satisfactorily even over a long period of operation and under unfavourable circumstances, a changeover has been made to using antifriction bearings to support the individual pedals and/or the shaft sections assigned thereto both on one another and in the bearing arms of a bearing bracket. Although this measure achieves the desired success in terms of it being possible for the pedals to be actuated smoothly and absolutely independently of one another, it is also associated with the disadvantage of a considerable increase in the production outlay for the foot-control unit, especially since the use of antifriction bearings, in particular needle bearings, makes it necessary to maintain tolerances which are difficult to guarantee in mass production.
An object of the invention is thus to improve a disengageable pedal support of the type mentioned in the introduction, which is also suitable for right-hand-drive vehicles in particular and is intended for pedals supported about concentric axes, to the effect that, on the one hand, it can easily be installed and removed without there being any need to maintain extremely narrow tolerances and, on the other hand, at the same time the situation where the pedal which is not actuated in each case is influenced or carried along unintentionally by the pedal which has just been actuated in each case is avoided even without the use of antifriction bearings.
This object may be achieved according to the present invention in that a first pedal, forming in particular a brake pedal, and a second pedal, forming in particular a clutch pedal, are mounted in a bearing bracket, which has two bearing arms, such that they can be pivoted independently of one another about concentric axes, via graduated supports formed by annular plain-bearing shells, it being the case that the bearing arms are provided, on their mutually facing sides, with laterally projecting bearing-eyelet continuations which accommodate the graduation, with the larger clear diameter, of the support-forming annular plane-bearing shells, and it also being the case that the support of at least one of the two pedals is designed as a plug-in support. The fact that, in the case of the design according to the invention of the support for the two pedals of a foot-control unit, each of the two pedals can be pivoted about a dedicated axis and is accommodated in dedicated bearings which are fixed in a rotationally secure manner in the respective bearing eyelet of the bearing bracket makes it possible, even when plain bearings are used, to prevent the pedals from influencing one another when one pedal is actuated in each case. Furthermore, the interlinked arrangement according to the invention of the pivot axes which are independent of one another also makes it possible to use single-part bearing shells for the support of the two pedals, with the result that the outlay necessary for the support can be kept low. Finally, as far as the installation and removal of the foot-control unit is concerned, a particular advantage is achieved by the support for at least one of the pedals being designed according to the present invention as a plug-in support, in particular to the effect that said pedal can be installed and removed without the aid of tools.
In a preferred realization of the present invention, it is further provided that the brake pedal is of two-part design, it being the case that a first, pedal-bearing half of the brake pedal is connected in a rotationally secure manner to a first bearing body and a second half of the brake pedal, said half forming the actuator lever for engaging the brake and/or actuating the brake booster, is connected in a rotationally secure manner to a second bearing body, which is spaced apart from the first bearing body, and it being the case that the two bearing bodies are coupled in a rotationally secure manner to one another by means of a polyhedral element engaging in them with a form fit, and are each accommodated in the respectively smaller-internal-diameter part of the plain-bearing shells, which are arranged in the two bearing arms of the bearing bracket and form graduated supports. In conjunction with the two-part design of the brake pedal, it is then further provided, as far as the design of the clutch pedal is concerned, in the case of said realization of the invention that by means of a tube which encloses both the first bearing body, connected in a rotationally secure manner to the brake pedal, and the second bearing body, connected to the actuating lever for engaging the brake, said actuating lever being spaced apart from the brake pedal, and which is arranged concentrically with the brake-pedal shaft, formed by the screw-bolt, the clutch pedal is accommodated in the respectively larger-internal-diameter part of the plain-bearing shells, which are arranged in the two bearing arms of the bearing bracket and form graduated supports.
In order to simplify the handling during the installation and removal of the foot-control unit, it may further be provided that the pedal lever of the clutch pedal is connected by means of welding to the tube, which is arranged concentrically with the brake-pedal shaft, to form a rigid unit.
As far as the design of a plug-in support for one of the two pedals of the foot-control unit, preferably for the pedal forming the single-part clutch pedal, is concerned, it is expediently provided that the bearing-eyelet continuations, which are arranged on the mutually facing sides of the bearing arms of the bearing bracket and accommodate the graduation of the support-forming annular plain-bearing shells, said graduation having the larger clear diameter and being assigned to the support of the tube, which forms a rigid unit with the clutch pedal, have a radial opening which is smaller than the external diameter of the tube, which is connected to the clutch pedal. In conjunction with such a design of the bearing eyelets, it is then further recommended that in the region of its two ends, which engage in the bearing-eyelet continuations, which are formed on the bearing arms of the bearing bracket, the tube, which is connected to the clutch pedal to form a rigid unit, is provided with two mutually opposite outer-circumference flattened formations such that the external diameter of the tube, over part of the outer circumference of the latter, is equal to or smaller than the clear width of the radial openings in the bearing-eyelet continuations of the bearing arms of the bearing bracket.
In accordance with the configuration of the bearing eyelets of the bearing bracket, in terms of the design or configuration of the plain bearings, which form the supports of the pedal support, it is provided that also the plain-bearing shells, which are arranged in the bearing eyelets of the bearing arms of the bearing bracket, have a radial opening in their region having the larger clear diameter which corresponds to the clear width of the radial opening of the bearing-eyelet continuations of the bearing arms of the bearing bracket.
The arrangement of the clutch-pedal-supporting tube within the pedal support is such that in relation to the radial openings in the bearing-eyelet continuations of the bearing arms and the radial openings in the plain-bearing shells, the two flattened formations of the external diameter of the clutch-pedal-supporting tube are arranged in a range which is located outside the normal-operation pivoting-angle range of the clutch-pedal support, such that the clutch pedal can only be released from its supports in a position in which it has been pivoted beyond its normal-operation pivoting-angle range.
In a further expedient single configuration, it may also be provided, as far as the design of a bearing spindle for the two-part brake pedal is concerned, that the first bearing body, which supports the brake pedal, and the second bearing body, which is spaced apart from the first bearing body and supports the actuating lever, are braced against the two end sides of a spacer sleeve by means of a screw-bolt passing through them, it being the case that the first bearing body, which supports the brake pedal, is provided with an internal thread and the head of the screw-bolt engages over the outer end side of the bearing body which supports the actuating lever. In the case of such a configuration, the two bearing bodies expediently have the spacer sleeve engaging over part of their length such that the spacer sleeve at the same time engages over those length sections of the two bearing bodies which pass through the bearing eyelets in the bearing bracket and thus, by way of its outercircumference surfaces, forms the bearing surfaces of a brake-pedal bearing shaft.
Finally, a further feature of the present invention is that the plain-bearing shells, which are arranged in the bearing arms of the bearing bracket, are each formed by a moulding made of a self-lubricating plastic material, and are provided with a radially directed opening merely in their graduated region assigned to the larger diameter.